Living With Beavers

“Beavers are a keystone species- that is, their presence and activities are so important to an ecosystem that their removal
leads to a loss of habitat for other species and a breakdown of ecological integrity.”
—Dave Foreman, Rewilding North America, 2004

The beaver, Castor canadensis, is the largest rodent in North America. Beaver are industrious engineers that prefer
certain woody species of vegetation for food and construction of their dam lodges, which they use for shelter and food storage. Use of woody
species for food and shelter modifies streams and surrounding woodlands. Modification often improves the health of crucial life-giving
riparian areas. Beaver dams can increase the amount of water in a given area, raising the water table and increasing water storage.
Beaver ponds can trap and store organic materials, nutrients, and sediment, thus filtering water and leaving downstream water cleaner.
Still pond water filters into the ground, recharging aquifers, and dams can improve rehabilitation of areas where vegetation has been
damaged. Beaver dams can also improve habitat for fish, amphibians, and invertebrates, birds and large land mammals. Beaver can also
provide a valuable fur resource, beaver ponds create diverse aquatic ecosystems, and beaver dams provide natural irrigation ponds.

Aside from the benefits beaver provide to the ecosystem, they can also be pests to humans coexisting in the same habitat. Dam building
can damage nearby lands by causing flooding, tree cutting, bank burrowing, and crop destruction. In Alaska, beaver are moving further
north as habitat changes and access to woody plants increase. Complaints in Alaska generally relate to flooding during spring break-up,
increasing giardia in the water supply, and decreasing access to traditional subsistence fishing areas by changing water flow
characteristics of streams.